The BBC here looks briefly at the study of aging in varying animal species - it mangles the scientific details in the usual fashion, but covers much of the territory: "From the moment they are born into the dense jungle of Central Africa, the biological clock is ticking for baby bonobos. A recent study, published in the journal Science, revealed that all primates - from men to monkeys - roughly age in the same way, with a high risk of dying in infancy, a low risk of dying as juveniles and then an increasing risk of dying as they aged. Some species though, have found a few tricks to help them play the aging game and extend their natural lifespans. By doing so, they can live for hundreds of years. While a select few, by some definitions, may already have become immortal. ... some species of bat [can] live for decades [and] the explanation may lie in the way bats protect themselves from protein damage, using special molecules called protein chaperones. ... Studies of the American lobster (Homarus americanus), have shown that its extreme longevity might be related to the expression of telomerase ... High concentrations of telomerase are found in cells that need to divide regularly such as organs and embryonic stem cells. Access to an elevated supply of telomerase would equip this crustacean with the ability to rebuild cells damaged by aging. The ability to repair cells in this way may help to explain why lobsters can live up to 100 years and are able to regrow limbs even at an 'old age'. ... Another oceanic resident, the quahog clam (Arctica islandica), is thought to be one of the longest lived metazoans of all. A recent study on this ancient clam, [which] lives more than 400 years, shows it has an increased resistance to oxidative stress. ... The reasons for the exceptional longevity in Arctica may have little to do with resistance to oxidative stress though. ... Instead, like in naked mole rats, it may be the integrity of the animal's proteins that may be the key, rather than damaging free radicals or antioxidants used to defend against them."